/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * libc/stdio/lib_libfwrite.c
 *
 *   Copyright (C) 2007-2009, 2011, 2013-2014 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <sys/types.h>
#include <stdbool.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#include "lib_internal.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Type Declarations
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Global Constant Data
 ****************************************************************************/

/****************************************************************************
 * Global Variables
 ****************************************************************************/

/****************************************************************************
 * Private Constant Data
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: lib_fwrite
 ****************************************************************************/

ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
#if CONFIG_STDIO_BUFFER_SIZE > 0
{
	FAR const unsigned char *start = ptr;
	FAR const unsigned char *src = ptr;
	ssize_t ret = ERROR;
	unsigned char *dest;

	/* Make sure that writing to this stream is allowed */

	if (!stream || (stream->fs_oflags & O_WROK) == 0) {
		set_errno(EBADF);
		goto errout;
	}

	/* Get exclusive access to the stream */

	lib_take_semaphore(stream);

	/* If the buffer is currently being used for read access, then
	 * discard all of the read-ahead data.  We do not support concurrent
	 * buffered read/write access.
	 */

	if (lib_rdflush(stream) < 0) {
		goto errout_with_semaphore;
	}

	/* Loop until all of the bytes have been buffered */

	while (count > 0) {
		/* Determine the number of bytes left in the buffer */

		size_t gulp_size = stream->fs_bufend - stream->fs_bufpos;

		/* Will the user data fit into the amount of buffer space
		 * that we have left?
		 */

		if (gulp_size > count) {
			/* Yes, clip the gulp to the size of the user data */

			gulp_size = count;
		}

		/* Adjust the number of bytes remaining to be transferred
		 * on the next pass through the loop (might be zero).
		 */

		count -= gulp_size;

		/* Transfer the data into the buffer */

		for (dest = stream->fs_bufpos; gulp_size > 0; gulp_size--) {
			*dest++ = *src++;
		}

		stream->fs_bufpos = dest;

		/* Is the buffer full? */

		if (dest >= stream->fs_bufend) {
			/* Flush the buffered data to the IO stream */

			int bytes_buffered = lib_fflush(stream, false);
			if (bytes_buffered < 0) {
				goto errout_with_semaphore;
			}
		}
	}

	/* Return the number of bytes written */

	ret = src - start;

errout_with_semaphore:
	lib_give_semaphore(stream);

errout:
	if (stream && (ret < 0)) {
		stream->fs_flags |= __FS_FLAG_ERROR;
	}

	return ret;
}
#else
{
	ssize_t ret = write(stream->fs_fd, ptr, count);
	if (ret < 0) {
		stream->fs_flags |= __FS_FLAG_ERROR;
	}

	return ret;
}
#endif							/* CONFIG_STDIO_BUFFER_SIZE */
